I/O 文件处理救助

Question

问题：副本中最后都会有重复内容，不知道怎么办。
代码如下：public class copy {

public static void main(String args[]) {
try{
FileInputStream inputStream=new FileInputStream(new File("飘.txt"));
FileOutputStream outputStream=new FileOutputStream(new File("test.txt"));
byte buf[]=new byte[1024];
while (inputStream.read(buf)!=-1) {
outputStream.write(buf);
}
outputStream.close();
System.out.println("end!");
}
catch(Exception e){
e.printStackTrace();
}
}}

Answer 1

int len = -1;
while ((len = inputStream.read(buf)) != -1) {
outputStream.write(buf,0,len);                
}

Answer 2

import java.io.*;public class copy {
     
    public static void main(String args[]) 
{
FileInputStream inputStream = null;
FileOutputStream outputStream = null;
        try
{
          inputStream = new FileInputStream(new File("飘.txt"));
          outputStream = new FileOutputStream(new File("test.txt"));
            byte buf[]=new byte[1024]; int len = 0;            while (len=inputStream.read(buf)!=-1) 
{
//这句话的意思是，写出去多少合适？写到我len=-1之前的数据
                outputStream.write(buf,0,len);               
            }
        }
        catch(Exception e)
{
            System.out.println(e.toString());
        }
finally
{
try
{
if(inputStream!=null)
inputStream.close();
}
catch (IOException e)
{
System.out.println(e.toString());
}
try
{
if(outputStream!=null)
outputStream.close();
}
catch (IOException e)
{
System.out.println(e.toString());
}
}
    }
}